PRAGUE (AP) — Two planes carrying dozens of parachutists collided in midair Thursday over western Slovakia, killing seven people, officials said. Slovak media reported 15 other parachutists missing and an aviation official said some reportedly survived by jumping out with their parachutes.

The crash took place Thursday morning about 0720 GMT (2:20 a.m. EDT) near the village of Cerveny Kamen, said Zuzana Farkasova, a spokeswoman for the Slovak firefighters. Rescue workers were using helicopters to reach the crash site, in the White Carpathians mountain range that forms the border with the Czech Republic.

Juraj Denes, an official with the Slovak Air and Naval Investigations Bureau, a government agency that investigates plane crashes, said according to preliminary information, about 40 people were on board two L-410 planes at the time of the collision, which occurred at an altitude of 1,500 meters (4,921 feet). He said the passengers on board were parachutists.

Some parachutists from one plane survived because they managed to jump out before the collision, Denes said. He did not give a specific number of survivors.

Juraj Gyenes of the same aviation agency told TA3 news television that the dead included the two crew members from both planes and three parachutists.

TA3 reported that 15 of the parachutists were still missing. It said all of them were training for this weekend's air show in nearby Slavnica.

"All of a sudden, I heard a big blow," one witness told TASR, the Slovak news agency, in a news video. "Then, it roared. I thought some pieces were falling, but it could be the parachutists."

Slovak Health Minister Viliam Cislak and Interior Minister Robert Kalinak were heading to the crash site.